This week pruning peach trees is on my schedule. I would like to offer my advice on this even though my trees are somewhat different than the standard orchard tree. One of my peaches is espaliered the other is being grown as a spindle in order to save space, so neither is an ideal peach.
The ideal peach is pruned into an "open bowl." the concept is that up to four or five main branches are selected that are stemming out at a similar height. These branches would hold a bowl like fingers without the main leader of the tree. What I am going to say next is going to freak you out if you have never done this before so brace yourselves.
You need to take everything above these branches out. Now remove any branches that cross. What you have left is the "open bowl" This might seem very extreme, but to produce quality fruit you will need to prune the tree back hard. The tree will put its energy into these branches and the fruit. Pruning the tree will strengthen the branches and increasing the productivity of the tree. The late summer will produce new growth and next February/March you will need to repeat this process.
During the late summer you can prune to promote dwarfing of the tree. At this time you could also "head" the branches by pruning them at the end back to a smaller stem that has a nice angle that you like (30-45 degrees)